The present invention relates to a nonwoven fabric manufacturing apparatus for continuously manufacturing nonwoven fabric.
FIG. 2 shows an example of a related art nonwoven fabric manufacturing apparatus. The nonwoven fabric manufacturing apparatus of FIG. 2 includes a melt blow portion 31, which has a spinning portion 32 and an air delivery portion 33. The spinning portion 32 receives molten resin from an extrusion machine 35, and spins fiber F. The air delivery portion 33 receives hot air from an air blower 36, and blows the hot air toward fiber F spun out from the spinning portion 32. As a result, the spun fiber F is blown onto the flat upper surface of a conveyor belt 34 located below the melt blow portion 31, which forms sheet-like nonwoven fabric C on the conveyor belt 34.
However, the air blown out of the air delivery portion 33 creates irregular turbulence on the conveyor belt 34, which may stir up the fiber F on the conveyor belt 34. This makes manufacture of a high quality nonwoven fabric C of uniform thickness and uniform fiber density difficult.
To prevent the fibers F from being stirred up by turbulence on the conveyor belt 34, it is effective to make the conveyor belt 34 of mesh material and apply suction to the conveyor belt 34 from below. However, in this case, the obtained nonwoven fabric C can be excessively flattened or have traces of the mesh.
On the other hand, aside from the nonwoven fabric manufacturing apparatus shown in FIG. 2, the nonwoven fabric manufacturing apparatus disclosed in Japanese Laid-Open Patent Publication No. 4-257362 is known. This nonwoven fabric manufacturing apparatus has a chamber with a large area opening and a small area opening, so that the cross-sectional area of the chamber decreases from the large area opening toward the small area opening. A spinning portion and an air delivery portion are located in the large diameter opening of the chamber. Fiber spun out of the spinning portion moves into the current of air blown out of the air delivery portion, passes through the chamber, and then exits the chamber through the small area opening. A pair of rollers is provided below the small area opening, so that fiber that has exited the chamber passes between the rollers and is sent to a collecting surface of a screen belt. Accordingly, sheet-like nonwoven fabric C is formed on the collecting surface.
In the case of the nonwoven fabric manufacturing apparatus of Japanese Laid-Open Patent Publication No. 4-257362, fiber that has exited the chamber through the small area opening passes between the rollers, and is then sent to the collecting surface. Therefore, even if the air from the air delivery portion creates turbulence, fiber is unlikely to be stirred up from the collecting surface. However, the nonwoven fabric manufacturing apparatus of Japanese Laid-Open Patent Publication No. 4-257362 has a disadvantageously complicated structure.